/projects

Projects & Operational Experience

Selected production incident case studies, laboratory environments and operational tooling focused on network security, secure connectivity and service continuity. Case studies are anonymized and describe my contribution alongside the teams involved.

production_incidents

Operational Case Studies

case-study-01.log

Overnight Warehouse PDA Outage

Investigated an overnight handheld-device outage, validated network connectivity and helped direct troubleshooting towards the vendor-managed application backend. Service was restored following vendor configuration changes and device restarts.

Network TroubleshootingDNSHandheld DevicesVendor Coordination

View incident details

Context

Warehouse handheld devices were unable to initialize their application, disrupting overnight operations. Initial troubleshooting needed to distinguish a connectivity issue from an application or backend failure.

My Contribution

I checked network and backend connectivity, investigated application initialization timeouts and reviewed hostname resolution behaviour. I documented the findings, supported coordination with the application vendor and tracked recovery with the operational team.

Resolution & Outcome

The vendor applied backend configuration changes and requested device restarts. The operational team confirmed that the handheld devices were working again. No network connectivity fault was identified during the investigation.

Key Takeaway

Structured validation helped narrow the investigation and direct the incident towards the team able to restore service.

case-study-02.log

Transport Dispatching IP Telephony Outage

Coordinated troubleshooting of a widespread Cisco IP phone outage affecting transport dispatching. The investigation covered switch-stack health, voice VLAN configuration and telephony services, with recovery confirmed before the night shift.

CiscoSwitchingVoice VLANCUCMIncident Coordination

View incident details

Context

Most dispatching IP phones were unavailable and displayed a ‘Host not found’ error. Restoring sufficient telephony capacity before the next operational shift was a key requirement.

My Contribution

I investigated endpoint behaviour, coordinated device reset tests and requested checks of switch connectivity and voice VLAN configuration. I followed the network provider’s intervention, tracked the remaining telephony impact and continued escalation to the voice support team after network connectivity had been restored.

Resolution & Outcome

The network provider corrected a software-version mismatch within the switch stack. The phone issue persisted despite subsequent port and voice VLAN checks. The voice provider then restarted Extension Mobility and Trust Verification Services across the telephony servers, restoring phone functionality before the night shift. Follow-up work increased diagnostic logging because the underlying service failure mechanism had not been conclusively established.

Key Takeaway

Restoring network infrastructure was an intermediate step. Recovery required continued investigation across both switching and telephony services, followed by operational confirmation.

case-study-03.log

Warehouse Handheld Connectivity — DHCP Investigation

Investigated wireless connectivity problems affecting warehouse handheld devices. LAN DNS validation and comparison with a previous incident supported a targeted DHCP/Infoblox escalation. The infrastructure team restored service by restarting DHCP services.

InfobloxDHCPDNSWireless ConnectivityIncident Analysis

View incident details

Context

Drivers and loading teams reported connectivity and login failures on wireless handheld devices. The investigation needed to distinguish a general backend or DNS issue from a problem affecting wireless clients.

My Contribution

I confirmed that the application hostname resolved from the internal LAN and compared this with the resolution failures reported on wireless devices. I reviewed a previous incident with similar symptoms, identified DHCP address availability on Infoblox as a likely investigation path and escalated the findings to the infrastructure team. I also tracked partial recovery, documented the remaining impact and coordinated the overnight handover with operational teams.

Resolution & Outcome

The infrastructure team restarted DHCP services on both Infoblox servers. The recorded resolution states that this freed IP addresses and restored service. The available evidence supports the DHCP investigation path, although detailed lease and pool diagnostics were not included in the incident record.

Key Takeaway

Comparing working and affected client environments, then using previous incident findings, helped produce a focused escalation with clear operational follow-up.

controlled_environments

Labs & Tooling

project-01.log

Multi-Site Infrastructure Lab

Operational

Multi-site environment replicating segmented networks, routed domains and secure inter-site connectivity. Scope includes: - IPSec site-to-site tunnels - Policy-driven firewall enforcement - Centralized logging & visibility - SNMP monitoring - Segmentation and traffic boundary validation Purpose: simulate real production behavior under controlled conditions and validate secure connectivity patterns at scale.

CiscoFortinetVPNLinuxMonitoring

~/labs/multi_site_infrastructure_lab

project-02.log

Network Automation Toolkit

Ongoing

Operational Python toolkit designed to improve reliability, consistency and speed in network operations. Focus: repeatability, execution control and reduction of human error in operational tasks. Includes: - Automated configuration backups - Compliance & drift detection - Inventory parsing - CLI-driven bulk operations - Structured validation workflows Extended use: - Store-level connectivity diagnostics - Multi-node validation (routers, nodes, endpoints) - Rapid P2 troubleshooting support

PythonAutomationCLIStructured Configs

~/labs/network_automation_toolkit

project-03.log

Secure Remote Access Validation Lab

Operational

Comparative testing of secure remote access architectures: - Zscaler ZIA / ZPA - IPSec VPN - SSL VPN Designed to analyze real-world remote connectivity patterns, proxy behavior and secure access strategies. Validation focus: - Policy behavior - Authentication flows - Traffic inspection paths - User experience vs security trade-offs - Access segmentation enforcement

ZscalerVPNFirewallAccess Control

~/labs/secure_remote_access_validation_lab

project-04.log

Incident Response & Log Analysis Playground

Scenario Ready

Controlled environment for: - Log correlation - Syslog analysis - Packet capture & replay - Incident simulation - Structured troubleshooting workflows Objective: strengthen observability discipline and improve P2 incident analysis across network security operations.

LinuxSyslogTraffic CaptureAutomation

~/labs/incident_response_playground

project-05.log

Firewall Policy Optimization Study

Validation Phase

Structured review and refinement of firewall rulebases. Focus areas: - Rule cleanup & lifecycle management - NAT optimization - Segmentation reinforcement - Policy overlap detection - Change impact validation Designed to improve clarity, performance and security posture in firewall environments.

FortinetAlgoSecSegmentation

~/labs/firewall_policy_optimization

View all repositories on GitHubgithub.com/SecureIT-Hub